Topic: Oil in alternator - affect charging ability?

[nhg2112]

Long story short my charging system is putting out around 11v. I haven't pulled everything apart and started the diagnosis yet but I'm curious about something:

One of my bottom galley plugs has a bad o ring and is leaking a small amount of oil into the alternator assy. Would this oil have any affect on it's ability to put out a strong charge?

Not trying to start a diagnosis thread, just curious about the oil...

[nccb]

The stator cover has oil behind it so the alternator would be in some oil normally. . .

[Bodi]

depends on the model whether the alternator gets any oil. regardless, it won't hurt anything.

[nccb]

depends on the model whether the alternator gets any oil. regardless, it won't hurt anything.

good to know. so on my 750 K4 there is oil.  I guess on a 550 it wouldn't because of the starter clutch?

[nhg2112]

Should have specified - this is a 500/550 so it's a dry alternator.

Thanks for the quick response. It doesn't make sense that oil would affect the magnetic voodoo that happens in there but ya never know 

[TwoTired]

I suspect modern oils may have an effect on the winding insulation, which would cause it to breakdown and allow windings to short against other windings or the winding's frame.

None of the stator windings should have continuity to the engine case.  If so, you have a problem.  The stator can be tricky to measure for shorted windings since the resistance is very low (~ .35Ω, which is about what meter lead resistance is).
Need a milliohmmeter, or measure the AC voltage the windings produce.

May as well measure the field winding resistance, too.

I don't know how you determined the charging system is putting out 11v.  Any battery that measures this voltage is seriously depleted, and will take a good long while to raise it's voltage (assuming the battery is good), and you just can't test a charging system with a bad or depleted battery.